Congrats!! 6 months is great.
I am somone who knows I will have to quit soon. Alcohol is depressing me and destroying my pesonality. I did quit for about 5 weeks and then went back to school and visited my frat house (bad idea).
For those 5 weeks I felt that I wasn't doing that great and was lonely and angry all the time. It is good to know that at 6 months it gets better than it does at 3 months.